Propeller with helicoidal torsion



R. P. PESCARA PROPELLER WITH HELICOIDAL TOR'SION `Fi1ed Fem-2s, 1921 I Feb. 10.- 19.25.- v

Patented 'Fea io, 1925;.

UNITED STATES r PATENT oFFiCi-z.

itAUn rArEnAs PESCARA, or BARCELONA, SPAIN.

PRQPELLER WITH HELICOIDAL 'roBsIoNL Appiication mea February 28,.'1921. serial No. 448,641?.

To all 'whom z' may concer/n.'

Be it known that RAUL PArERAs PESCARA, citizen of Argentina, residing at Barcelona, Spain, Calle Buenasuerte 20 (S. M.), has

invented certain new and useful lmprove-v 'in flying machines of the helicopter type,

and is particularly directed to a construction wherein the` efficiency of the propeller is materially increased throught-he control of the helicoidal torsion.

In an application filed b 28, 1921, Serial No. 448,646, a multi-plane propeller in which means are provided for controlling thetwisting of the blade, and the present application is directed more particularly to the specific means for this purpose, which is generally described in the above noted application.

In the drawings:

Fig. 1 is a view in elevation of a multiplane propeller constructed in accordance with the present invention.

Fig. 2 is a plan of one of the blades, the covering being removed.

me February Figs. 3 and 4 are respectively plans and transverse sections illustrating the torsion modifying means.

Fig. 5 is a transverse section through one of the blades.

As set forth inthe application above referred to, the present propeller is shown as of the biplane type with lower and upper blades 10 and 11 radiating from an enlargement8 of a hub 9 and connected by struts ,12 having diagonal tie rods 13. Eachblade is made up of a frame connected by ribs 23,'

which as indicated in F ig. 5. are each formed of a wooden web 24 exteriorly -strengthened by a wooden ledge 25. Tubes 26--27 pass through and connect the ribs. The blade vis rotatably supportedbn a shaft 28 and held thereon against endwise movement by ball bearings 31---32 Special ribs 29 are provided through whichvthe shaft 28 passes and in which it may be mounted through bronzev bearings. l

A, cable 34 extends vlongitudinally of the blade andis connected to suitable operating mechanism arranged in the enlargement 8 of the hub 9, so that the cable may be drawn upon at will, or relieved of suchtension have described` as may be desired. The cable is designed to operate certain screw elements for imparting a torsion or twisting movement t0 the blade, these screw elements being more particularly shownin Figs. 3 and 4. The screw elementsY constitute a member including encircling and free bearing sleeve portions B8- 39, which embrace 'the shaft 28, and arms 32 extending therefrom to a portion having rigid connection with the tube 26.

This member is formed adjacent the tube 26 -I and centrallyl between the arms 32 with the section 40 having a vworm tooth formation on its inner edge. The cooperatin member includes a 'segment portion 31 having a threaded surface cooperating with the worm thread `surface ofsection 40, this member Y' 31 being pivotally supported at 35 upon a pin 36 extending transversely thro h the shaft 28. The member 31 is exten ed beyond the pivotf36 in the form of an arm to be connected at 37 to the cable 34.

Obviously, in movement of the cable, a corresponding movement is imparted to the elements 31, which through the worm and thread connection, with the tube 26, that is,

with the blade proper, a twistingor torsional movement is imparted to said blade.

If it is desired to provide a variation of theV helicoidal torsion of the blade surface, the successive endless screw members mayA be given different pitch, whereby various sections of the blade are given a variable torsion or twisting, as will be evident.

' Through this control, it is apparent that the blades may be operated lain, that is, without torsion, through the identical pitch of the respective screw elements 31-or may be given any degree of torsion, either negative orpositive within the range of the screw members, and this torsion may be varied for different sections ofthe blade, all as will be understood from the above description. The negative torsion is particularly desirable in the descent of the machine in rotative gliding flight; while positive torsions are particularly desirable in forward driving and in landing, it being highly important under the latter condition that the torsion of the blades which was negative during descent is made suddenly positive just before landing, thereby utilizing the energy stored in the blades .during their rotation in descent toy neutralize the similar energy of ing shock.

Claims:

1. A helicopter having propellers, the blades of each propeller being mounted for movement .about a shaft, screw members suported for pivotal movement on the sha a cooperating worm thread member rigid with the blade, and a cable for simultaneously operating all of said screw members whereby to impart a twisting action to the blade with respect to the shaft.

2. A helicopter having blades of each propeller being mounted for movement about a shaft, screw members propellers, the` having a worm thread and a rotatable connection with the bar, a member pivot-ally mounted on the bar provided with a worm thread cooperating with the worm thread of the first member, and means for operating the pivoted member to partially rotate the blade on the bar.

4. A propeller blade mounting, including a blade carrying bar, a blade rotatable thereon, members carried by the blade, each having a worm thread and spaced arms rotatably mounted on the bar, members pivotally mounted on the bar between the arms of each blade carried member and having a Worm thread cooperating with the Worm thread of the blade carried member, and operating means for the pivotal members for impartinga movement to the blade relative to the bar.

In testimony whereof he aiixes his signature in presence of two witnesses.

RAUL PATERAS PESCARA.

Witnesses T. BAUDRY, UyANGEL BELNnR. 

